module RCNB

RCNB模块

## Example “`ruby require 'rcnb'

RCNB.encode('Who NB?') # => ȐȼŃƅȓčƞÞƦȻƝƃŖć RCNB.decode('ȐĉņþƦȻƝƃŔć') # => RCNB! “`

Constants

VERSION: @private

Public Class Methods

decode(str,encoding=nil) click to toggle source

将RCNB密文解码为文本 @param str [String] 密文 @param encoding 文本编码 @return [String] 文本

# File lib/rcnb.rb, line 146
def self.decode(str,encoding=nil)
  raise ArgumentError,'invalid length' unless (str.size & 1).zero?
  arr=[]
  0.upto( (str.size>>2)-1 ) do |i|
    i4=i*4
    short=decodeShort(str[i4,4])
    arr<< (short>>8)
    arr<< (short&0xFF)
  end
  arr<< decodeByte(str[-2,2]) unless (str.size & 2).zero?
  result=arr.pack('C*')
  if encoding
    result=result.force_encoding(encoding)
    result=result.encode(__ENCODING__)
  else
    result=result.force_encoding(__ENCODING__)
  end
  result
end

encode(str,encoding=nil) click to toggle source

将文本编码为RCNB密文 @param str [String] 文本 @param encoding 文本编码 @return [String] 密文

# File lib/rcnb.rb, line 130
def self.encode(str,encoding=nil)
  str=str.encode(encoding) if encoding
  arr=str.unpack('C*')
  result=''
  0.upto( (arr.size>>1)-1 ) do |i|
    i2=i*2
    result+=encodeShort( arr[i2]<<8 | arr[i2+1] )
  end
  result+=encodeByte(arr[arr.size-1]) unless (arr.size & 1).zero?
  result
end

Private Class Methods

decodeByte(c) click to toggle source

# File lib/rcnb.rb, line 89
def self.decodeByte(c)
  nb=false
  idx=[ IR[c[0]],IC[c[1]] ]
  if !idx.all?
    nb=true
    idx=[ IN[c[0]],IB[c[1]] ]
  end
  raise ArgumentError,'not rc/nb' if !idx.all?
  result=nb ? idx[0]*SB+idx[1] : idx[0]*SC+idx[1]
  raise ArgumentError,'rc/nb overflow' if result>0x7F
  nb ? result|0x80 : result
end

decodeShort(c) click to toggle source

# File lib/rcnb.rb, line 102
def self.decodeShort(c)
  reverse=!IR[c[0]]
  if reverse
    idx=[ IR[c[2]],IC[c[3]],IN[c[0]],IB[c[1]] ]
  else
    idx=[ IR[c[0]],IC[c[1]],IN[c[2]],IB[c[3]] ]
  end
  raise ArgumentError,'not rc/nb' if !idx.all?
  result=idx[0]*SCNB+idx[1]*SNB+idx[2]*SB+idx[3]
  raise ArgumentError,'rc/nb overflow' if result>0x7FFF
  reverse ? result|0x8000 : result
end

encodeByte(i) click to toggle source

# File lib/rcnb.rb, line 60
def self.encodeByte(i)
  raise ArgumentError,'rc/nb overflow' if i>0xFF
  if i>0x7F
    i&=0x7F
    d,m=i.divmod(SB)
    "#{CN[d]}#{CB[m]}"
  else
    d,m=i.divmod(SC)
    "#{CR[d]}#{CC[m]}"
  end
end

encodeShort(i) click to toggle source

# File lib/rcnb.rb, line 72
def self.encodeShort(i)
  raise ArgumentError,'rc/nb overflow' if i>0xFFFF
  reverse=false
  if i>0x7FFF
    i&=0x7FFF
    reverse=true
  end
  result=[
    CR[i/SCNB],
    CC[i%SCNB/SNB],
    CN[i%SNB/SB],
    CB[i%SB]
  ]
  result=[ result[2],result[3],result[0],result[1] ] if reverse
  result.join
end